[pianotech] Wixie inclinometer

John Delacour JD at Pianomaker.co.uk
Wed Jul 14 11:42:12 MDT 2010


At 09:41 -0400 14/7/10, jimialeggio wrote:

>... I guess it turns out the the calc uses vectors rather than the 
>high school trig we are usually use.
>
>Geeks who understand vectors seem to do all kinds of cool and 
>bizarre things with them...

Sure, but vectors (as such) don't really come into this; it's simply 
the same old basic trig applied to a very elementary mechanical law. 
Most of us were taught both before we ever heard of a vector.

The distance of the string/bridge contact above the horizontal would 
be calculated by multiplying the speaking length by the SINE of the 
angle, so the longer the string, the greater that distance is for a 
given angle, but by elementary mechanics the force (the tension) will 
be shared in the same proportion between the x axis and the y axis, 
so the length of the string is immaterial; only the angle and the 
tension are needed for the calculation.  In this case we are dividing 
the force between the y axis and a line sloping up from the x axis, 
so we use the SINE rather than the TANGENT.

JD




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